1. Field of the Invention
The present disclosure is related to transparent laminate structures. More particularly, the present disclosure is related to transparent laminate structures that resist delamination.
2. Description of Related Art
Transparent laminate structures such as those used in windows and transparent armor are commonly used in a variety of commercial, industrial, and military applications. These structures are typically comprised primarily of glass layers and plastic layers bonded together with polymer interlayers where these interlayers are typically on the order of a magnitude thinner than the glass and plastic layers. The transparent laminate structures can also include a frame, which allows connection of the structure to a vehicle or building. For clarity of discussion the present application shall use the term “transparent laminate structure” to refer to the transparent laminate itself, also known in the art as a “glazing”, without any frame component.
The glass layers can be made of glass, glass-ceramics, and combinations thereof. The plastic layers can be made of polycarbonate (PC) or polymethyl methacrylate (PMMA), also known as acrylic glass, which are on the order of the thicknesses of the glass layers. These transparent plastic layers are typically within the structure, protected along their faces from exposure to the environment by the outer glass layers.
The interlayers can be made of a variety of different materials such as, but not limited to aliphatic polyether polyurethanes, polyvinyl butyrals, ethylene/methacrylic acid copolymers, and silicones.
These laminate structures can lose their value when the layers de-laminate from one another and/or when one or more of the layers suffers from a loss in transparency.
For example, the de-lamination of the various layers that make up the structure can reduce the transparency and/or reduce the rigidity of the structure, rendering the structure useless for its intended purpose.
Similarly, the plastic layers can themselves become cloudy and/or lose its structural rigidity. For instance, repeated exposure of polycarbonate to high temperature water vapor can create crazing, which manifests itself as surface clouding and ultimately a loss of physical strength properties. While the transparent plastic layers may be protected along their faces from exposure to the environment by the outer glass layers, the edges of many prior art laminate structures remain the primary area of ingress for water vapor.
In sum, prior art transparent laminate structures are exposed to various environments such as humidity and water, especially when combined with elevated temperature and/or exposure to ultra violate (UV) light, that are known to adversely affect the interlayers and/or the transparent plastic layers.
Accordingly, it has been determined by the present disclosure that there is a continuing need for transparent laminate structures that overcome, alleviate, and/or mitigate one or more of the aforementioned and other deleterious effects of prior art transparent laminate structures.